In order to display "<" or ">" in the markup string then use then escape codes or &lt; and &gt; -also note, the code must be terminated with a semicolon. The equivalents of \n and \r are &#13; and &#10;.

<span> Attributes

font, font_desc

A font description string, such as
"Sans Italic 12". Note: Any other span attribute will
override this description. So if you have "Sans Italic" and
also a style="normal" attribute, you will get Sans normal,
not italic.

font_family, face

A font family name

font_size, size

Font size in 1024ths of a point, or
one of the absolute sizes 'xx-small', 'x-small', 'small', 'medium',
'large', 'x-large', 'xx-large', or one of the relative sizes
'smaller' or 'larger'. If you want to specify a absolute size, it's
usually easier to take advantage of the ability to specify a partial
font description using 'font'; you can use font='12.5' rather
than size='12800'.

font_style, style

One of 'normal', 'oblique', 'italic'

font_weight, weight

One of 'ultralight', 'light',
'normal', 'bold', 'ultrabold', 'heavy', or a numeric weight

An RGB colour specification such as
'#00FF00' or a colour name such as 'red'

background, bgcolor

An RGB colour specification such as
'#00FF00' or a colour name such as 'red'

underline

One of 'none', 'single', 'double',
'low', 'error'

underline_color

The colour of underlines; an RGB
colour specification such as '#00FF00' or a colour name such as 'red'

rise

Vertical displacement, in 10000ths of
an em. Can be negative for subscript, positive for superscript.

strikethrough

'true' or 'false' whether to strike
through the text

strikethrough_color

The colour of strikethrough lines; an
RGB colour specification such as '#00FF00' or a colour name such as
'red'

fallback

'true' or 'false' whether to enable
fallback. If disabled, then characters will only be used from the
closest matching font on the system. No fallback will be done to
other fonts on the system that might contain the characters in the
text. Fallback is enabled by default. Most applications should not
disable fallback.